BUG #11696: C++ Linking issue - cant find ref to basic_tranaction

The following bug has been logged on the website:

Bug reference: 11696
Logged by: Colin Attwell
Email address: colin(at)ska(dot)ac(dot)za
PostgreSQL version: Unsupported/Unknown
Operating system: Debian Linux "Squeeze"
Description:

Ver 8.4.21squeeze:

Invoking: GCC C++ Linker
g++ -L/usr/lib -o"DATA_LOGGER" ./trunk/updateDB.o -lpthread -lpqxx
./trunk/updateDB.o: In function `transaction':
/usr/include/pqxx/transaction.hxx:104: undefined reference to
`pqxx::basic_transaction::basic_transaction(pqxx::connection_base&,
std::basic_string<char, std::char_traits<char>, std::allocator<char> >
const&, pqxx::readwrite_policy)'
collect2: ld returned 1 exit status
make: *** [DATA_LOGGER] Error 1

Which other library should be included to find basic_transaction?

Thanks